Commit a4d906c1 authored by Deb Mukherjee's avatar Deb Mukherjee
Browse files

Minor change in forward updates

Removes the case of coding prob = 0 for forward updates, since that
is not an allowed probability to code.
Slightly improves efficiency but may not matter in practice.

Change-Id: I3b4caf82e8f0891992f0706d4089cc5a27568dba
parent 551f37d6
......@@ -156,13 +156,14 @@ static int merge_index(int v, int n, int modulus) {
}
static int inv_remap_prob(int v, int m) {
const int n = 256;
const int n = 255;
v = merge_index(v, n - 1, MODULUS_PARAM);
m--;
if ((m << 1) <= n) {
return inv_recenter_nonneg(v + 1, m);
return 1 + inv_recenter_nonneg(v + 1, m);
} else {
return n - 1 - inv_recenter_nonneg(v + 1, n - 1 - m);
return n - inv_recenter_nonneg(v + 1, n - 1 - m);
}
}
......
......@@ -265,7 +265,7 @@ int count_term_subexp(int word, int k, int num_syms) {
static void compute_update_table() {
int i;
for (i = 0; i < 255; i++)
for (i = 0; i < 254; i++)
update_bits[i] = count_term_subexp(i, SUBEXP_PARAM, 255);
}
......@@ -277,9 +277,11 @@ static int split_index(int i, int n, int modulus) {
}
static int remap_prob(int v, int m) {
const int n = 256;
const int n = 255;
const int modulus = MODULUS_PARAM;
int i;
v--;
m--;
if ((m << 1) <= n)
i = recenter_nonneg(v, m) - 1;
else
......
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